Mexican President Vicente Fox's effort to reach agreement with Washington to provide legal status to millions of undocumented Mexican workers in the United States has stalled in recent months. Mexican officials still speak confidently of making progress this year. But in the southwestern United States, U.S. immigration experts see little chance for a broad agreement at a time when the United States is tightening border controls.

The Fox administration continues to speak optimistically about an immigration accord, while pro-immigrant groups in the United States lament new restrictions at the border that have made crossing more difficult. Some human rights groups have complained that the extra security is an over-reaction, since none of the terrorists who carried out the attacks on September 11 entered the United States from Mexico.

But U.S. authorities on the border remain on high alert. Border expert Louis Sadler, who teaches history at New Mexico State University, says the security measures are appropriate, because drug and immigrant smugglers could help terrorists.

"I think there is some danger, in the sense that these smugglers are a pretty crass bunch, and they will take money from anyone, without much thought," he said. "And they could care less whether an individual might, frankly, harm Mexico or the United States."

Mr. Sadler says drug smugglers continue to get around 80 percent of their cocaine shipments across the border, so they could do the same with weapons or explosives. The border, he says, has a long tradition of smuggling, and there are not enough agents to patrol the entire 3,000-kilometer line.

Mexican officials say the security issue only enhances their position. They favor more cooperation on border security as part of an overall agreement to "regularize" immigration. They say it is not in the best interests of the United States to have four or five million undocumented Mexican workers in the country. It would be better, they say, to provide some sort of amnesty, or at least temporary legal status, to these people, in order to keep track of them.

Juan Hernandez is director of President Fox's office for Mexicans Living Abroad. He says an immigration agreement would not only help protect the United States, it would help both nations to grow economically.

"We need to work very hard on this partnership for prosperity, in which we 'grow the pie,' as Vicente Fox says, in which we bring greater prosperity to Mexico, but also greater prosperity to the United States," he said.

Louis Sadler says such a broad proposal may eventually find acceptance, but that, for now, Mexico might be better off proposing something more modest.

"Given the events of September 11, I think it quite unlikely that there will be a widespread amnesty being put in place in the near future," he said. "I think, maybe, this is one of those situations, in which we should crawl a little bit before we learn to walk, in which both sides try to take some small, incremental steps; then maybe we can begin to deal with the larger problem."

Once the security problem is solved, Mr. Sadler says, there are many reasons why both countries might want to consider a new immigration arrangement. He says some U.S. employers rely on the low-wage immigrants, while Mexico also relies on the money sent home by the workers. Last year, remittances from Mexicans in the United States reached eight-billion dollars.

But Mr. Sadler says the movement of people north from impoverished states in southern Mexico has put strains on Mexican border states like Chihuahua and Sonora.

"The net effect of this is that these border states, like Chihuahua, have been overwhelmed by population," he said. "They cannot provide the social infrastructure to provide people with adequate housing and schools, and so forth. All of this is part of the same kind of phenomenon. It has not been good for Mexico, frankly, and there ought to be a better way."

In the end, Mr. Sadler says, a guest-worker program, similar to the so-called Bracero program of the 1940s might be the best solution. Through such a program, Mexican workers would be given legal permits to live and work in the United States for set periods of time. This kind of proposal, he says, might meet with some degree of acceptance in Washington, even among immigration critics, whereas more comprehensive plans most likely would meet with stiff opposition.